An interesting factoid about presidential tenures is that John Adams's tenure was shorter than that of all other presidents who served for one full term because 1800 was not a leap year.
Same with William McKinley if he either just served just 1 full term, that contained the year 1900 (not a leap year), or if he was able to serve out his 2nd term. Then he would have been prez for 2,921 days and not 2,922. This remains unnoticed in any list since he was shot in September 1901. Bill Clinton was able to serve 2,922 days because 2000 was leap year or divisible through 400.
I didn't actually know that before I saw the list of presidents by time in office a few years ago.
Franklin Roosevelt's second term was shortened by the 20th amendment by about six weeks. Of course it didn't have an impact since was reelected twice after that. However, it did shorten John Nance Garner's vice presidency compared to all other vice president that served two terms.
